246 



HARDWICKE'S SCIENCE-GOSSIP. 



females, woe to the former ! Here, if uot among 

 men and women, the gentlemen belong to the 

 weaker sex, and are quickly put out of the way by 

 their termagant wives, who then as speedily turn 

 their arms against each other. "We have watched 

 the habits of the Mantis (observes E. Blanchard 

 in his "Histoire des Insectes ") during several 

 months, and find that they can support a condition of 

 famine for a long period : I allude particularly to 

 Mantis religiosa and Emptisa panperata. On pre- 

 senting them with a number of flies, after depriving 

 them of food for several days, they would devour 

 seven or eight in a few seconds, but leave the rest 

 undisturbed until the following day. 



Near the equator it would seem the ferocity of 

 these creatures incites them to the capture of 

 animals not generally considered legitimate insect 

 booty, as I gather from the following relation, taken 

 from Tascheuberg's " Leben der Insekten." " Bur- 

 nieister describes a species of Mantis (Jf. argentina, 

 Burm.) from Buenos Ayres, about three inches long 

 and of a light green colour, of which he records a 

 most interesting anecdote, on the authority of an 

 Englishman, by name Hudson, in whose veracity 

 he has the utmost confidence. Mr. Hudson was 

 sitting one evening, between eight and nine o'clock, 

 outside the door of his residence, a villa in the 

 neighbourhood of Buenos Ayres, when his attention 

 was called to a small bird, Serpopahga subcristata, 

 which was shrieking and fluttering on a bough 

 over his head. Carious to ascertain the cause of 

 the disturbance, Mr. Hudson procured a ladder, 

 and having ascended, a remarkable sight met his 

 view. The bird had been seized by a female Mantis, 

 which, while it retained its hold on the tree with 

 its four hind legs, held the bird with so firm a 

 grasp round the neck by means of its long forelegs 

 that the heads of the two animals were closely pressed 

 together. The skin of the Mantis was torn to 

 tatters {in Fetzeii zerrissen), and the head picked 

 open by the bird ; but whether this had occurred 

 before or during the combat does not appear. Of the 

 fact itself Burmeister was well able to judge, for 

 Mr. Hudson transmitted to him both the insect and 

 the bird, which had been. so strangely captured." 



The various species of Mantis are scattered 

 widely over the face of the earth, from the equator 

 to the middle of Europe. Mantis religiosa has 

 been found in the neighbourhood^of Vienna; and 

 both it and M. oratoria inhabit the forest of Eon- 

 tainebleau, just south of Paris. 



Empusa differs from the true Mantids in having 

 the upper part of the head prolonged into a kind 

 of upright horn ; the antennae too of the male 

 insects are beautifully pectinated. Empusa gongy- 

 lodes, 111. resides in India, E. pauperata. 111., in 

 Southern Europe and North Africa. 



lichen Abbas. W. W. Spicer, 



DR. KINAHAN ON GUANO DEPOSITS OF 

 THE CHINCHAS ISLANDS. 



f\^ account of the gradual diminution of guano, 

 ^^ the origin of the deposits is interesting. It 

 s generally supposed that guano is a large ac- 

 cumulation of the excrements of sea-birds; but 

 in a paper published in the " Journal of the Boyal 

 Dublin Society," July, 185G, the late J. B. Kinahan, 

 M.B., M.R.I.A., proved that such is not the origin 

 of the guano on the Chinchas Islands, Peru, and the 

 following is an epitome of this author's paper on 

 the subject :— 



After a sojourn of some months on the coast of 

 Peru, and a careful examination of the guano de- 

 posits, my observations there have led me to reject 

 almost entirely the commonly received opinion that 

 this substance owes its origin to the deposits of 

 sea-fowl, though I would not for a moment assert 

 the same of all guano; as the great difference 

 observable between, for instance, the Ichaboe and 

 Peruvian guanos would seem to point to a different 

 origin of those deposits. 



The Chinchas Islands are three in number, and 

 lie about 12 miles off the coast of the mainland, in 

 latitude 13° 4-1' south, and longitude 76° 13' west, 

 constituting one of the rocky groups which here 

 stud the ocean. In their general physical character 

 they resemble each other, all being surrounded for 

 the greater part by precipitous, generally inacces- 

 sible cliffs, with one or more sandy bays on each 

 island ; the latter are, however, in most cases, unap- 

 proachable by boats, on account of the surf and the 

 rocks which bar their entrances. 



Rising gradually up from the edge of the highest 

 cliffs, some in places over 200 feet high, which for 

 the most part are at the eastern end of the islands, 

 are the guano-beds. . This deposit covers the 

 greater part of the sea-faces of the islands, but 

 leaving certain headlands completely bare, — the 

 bare knolls varying much in their proportionate 

 height and size. On the north island the guano 

 deposits occur as a long ridge, with lateral spurs, 

 its greatest thickness being about 200 feet, and 

 sloping suddenly down towards the sandy bays 

 already mentioned. These hills are all stratified, 

 the strata running horizontally, and varying in their 

 colour and size, being from one to about six inches 

 thick, and from a dirty white to a darkish brown in 

 colour. In the interior of the hills the guano is 

 dry, and so hard as to require the pick and shovel, 

 while on the surface it is generally loose and fri- 

 able, being loosest on the sides of the hills nearest 

 the sandy coves ; but the strata of one hill appear 

 as though they had once been continuous with 

 those of the others. The underlying rocks of which 

 the original islands are formed, are dark red por- 

 phyritic granite, overlaid in places by a coarse sand- 



